package edu.cque.sp06zuul.ex;

import edu.cque.sp01.web.util.JsonResult;
import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * @author Hua
 * @create 2022-08-19 14:10
 * 模块发生异常后的zuul降级处理
 */
@Component
public class ItemFB implements FallbackProvider {
    /*
    设置针对哪个后台服务进行降级
        item-service: 只对商品服务降级
        * : 对所有服务都应用当前降级类
        null: 对所有服务都应用当前降级类
     */
    @Override
    public String getRoute() {
        return "item-service";
    }

    /**
     * 向客户端返回的响应数据
     *
     * @param route
     * @param cause
     * @return
     */
    @Override
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
        return new ClientHttpResponse() {
            @Override
            public HttpStatus getStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR;
            }

            @Override
            public int getRawStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.value();
            }

            @Override
            public String getStatusText() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.getReasonPhrase();
            }

            @Override
            public void close() {
                //可以关闭使用过的数据流  BAIS不占用底层系统资源,不用关闭
            }

            @Override
            public InputStream getBody() throws IOException {
                String json = JsonResult.build().code(
                        500
                ).msg("后台服务出错,稍后重试").toString();

                return new ByteArrayInputStream(json.getBytes("UTF-8"));
            }

            @Override
            public HttpHeaders getHeaders() {
                HttpHeaders headers = new HttpHeaders();
                headers.add("Content-Type", "application/json;charset=UTF-8");
                return headers;
            }
        };
    }
}
